Charles Darwin’s note-making system

For what I hope are obvious reasons, this post also appears on my Friends of Charles Darwin website.

Charles Darwin’s life and work must be one of the most well documented of any scientist. We still have his Beagle Journal, most of his notebooks, much of his vast correspondence, many of the annotated books from his personal library, many of his own loose papers and draft manuscripts, not forgetting, of course, all the wonderful books and papers he published. Heck, we even have his student bills from university!

During his many years of research, Darwin consumed and processed vast amounts of information, merging it with thoughts and research of his own to produce all manner of publications on subjects as apparently diverse as coral reefs, insectivorous plants, barnacles (both living and fossil), earthworms, orchids, cross- and self-fertilisation, human emotions, climbing plants, domestication, not to forget, of course, evolution by means of natural selection, and human evolution and sexual selection.

Despite long-term ill-health, Darwin managed to churn out an awful lot of top-rate material over the years. It seems remarkable he was able to keep track of so many diverse topics. Fortunately, Darwin’s life is so well documented, we have a pretty good idea of how he made and arranged his notes—a practice that Darwin himself briefly describes in his autobiography:

As in several of my books facts observed by others have been very extensively used, and as I have always had several quite distinct subjects in hand at the same time, I may mention that I keep from thirty to forty large portfolios, in cabinets with labelled shelves, into which I can at once put a detached reference or memorandum. I have bought many books, and at their ends I make an index of all the facts that concern my work; or, if the book is not my own, write out a separate abstract, and of such abstracts I have a large drawer full. Before beginning on any subject I look to all the short indexes and make a general and classified index, and by taking the one or more proper portfolios I have all the information collected during my life ready for use.

In other words, in modern note-making parlance, Darwin:

  • gathered loose slips of information in a number of different filed folders dedicated to particular topics of interest. These slips included notes, speculations and draft fragments of his own; interesting snippets from, and comments on, stuff he had read; and extracts from personal correspondence;
  • made brief source/literature notes which he filed either: a) in the back of the book concerned; or b) in a dedicated file (i.e. drawer). Note: As we shall see from his son Francis’s account of Darwin’s note-taking system, Darwin sometimes also filed particular source/literature notes in the appropriate topic-related folder(s).

In the following sections, I explore Darwin’s note-making in more depth before giving one example of how Darwin transformed some rough notes into a published text.

Darwin’s reference and source notes

Darwin read vast amounts of scientific literature and, by way of light relief, also enjoyed having family correspondence, novels and other non-specialist books read aloud to him by his wife, Emma, while he rested.

During and immediately following the two decades’ research that culminated in the publication of On the Origin of Species, Darwin maintained reading notebooks listing, in chronological order, the books and papers he had read. He recorded work-related reading on the left-hand pages and leisure reading on the right. At the back of the same book, he also maintained a list of work-related material he planned to read. These notebooks will no doubt have been invaluable to Darwin when trying to recall obscure references.

When reading, Darwin treated work-related books very much as tools to be used. So much so that he was not above tearing particularly thick books in half down the spine to make them easier to handle. Indeed, according to his son Francis, “He used to boast that he had made [his close friend the geologist Charles] Lyell publish the second edition of one of his books in two volumes, instead of in one, by telling him how he had been obliged to cut [the first edition] in half.”

Francis also explains how his father annotated his reading material, and, later, made and filed indexed, abstracted notes:

In each book, as he read it, he marked passages bearing on his work. In reading a book or pamphlet, &c., he made pencil-lines at the side of the page, often adding short remarks, and at the end made a list of the pages marked. When it was to be catalogued and put away, the marked pages were looked at, and so a rough abstract of the book was made. This abstract would perhaps be written under three or four headings on different sheets, the facts being sorted out and added to the previously collected facts in different subjects. He had other sets of abstracts arranged, not according to subject, but according to periodical. When collecting facts on a large scale, in earlier years, he used to read through, and make abstracts, in this way, of whole series of periodicals.

Darwin’s notebooks and research portfolios

In the early days of his research into transmutation (i.e. evolution), at a time when he was still trying to identify a mechanism for evolutionary change, Darwin began to keep a number of transmutation notebooks in which he jotted down ideas, reading notes, and other information that seemed relevant to the general topic in hand. As he writes in his autobiography:

My first note-book was opened in July 1837. I worked on true Baconian principles, and without any theory collected facts on a wholesale scale, more especially with respect to domesticated productions, by printed enquiries, by conversation with skilful breeders and gardeners, and by extensive reading. When I see the list of books of all kinds which I read and abstracted, including whole series of Journals and Transactions, I am surprised at my industry.

Although Darwin continued to maintain a number of notebooks on various topics, shortly after his 1838 Eureka moment in which he identified a mechanism for evolution that he dubbed Natural Selection, he seems to have realised bound notebooks would be too restrictive when making notes for what was to become a twenty-year research programme. Instead, as we have already seen, he began to maintain a series of different loose-leaf portfolios dedicated to individual research topics.

It wasn’t just work-related textbooks that Darwin mistreated abysmally. Once he had begun his new system of collecting notes on loose slips of paper, he was not above tearing pages out of his old notebooks to file in the relevant portfolio. For example, on the inside cover of his famous Notebook B (1837–38), which contains his iconic ‘I think’ evolutionary tree diagram, Darwin noted:

All useful Pages cut out Dec. 7th. /1856/

(& again looked through April 21 1873)

Indeed, so useful does Darwin seem to have found his final (1839–41) notebook on transmutation that he tore it completely apart for filing in his various research portfolios.

Darwin adopted a very much top-down approach when researching and planning his never-to-be-completed ‘Big Book’ on species—an ‘abstract’ of which, he would later publish as On the Origin of Species. He had a broad outline for the book in mind, so arranged his portfolios to reflect the various planned chapter topics. The general idea was, once Darwin came to start writing a chapter, he would be able to open the corresponding portfolio, shuffle the various loose slips of paper about, and come up with a detailed outline for that chapter.

Darwin was so convinced of the usefulness of this technique that, in 1864, when trying to convince his close friend Thomas Henry Huxley to write a book on zoology aimed at a general audience, he suggested:

If you were to keep a portfolio open for a couple of years, and throw in slips of paper as subjects crossed your mind, you would soon have a skeleton (and that seems to me the difficulty) on which to put the flesh and colours in your inimitable manner.

In his Reminiscences, Francis Darwin also describes his father’s use of portfolios, and how, in later life, Darwin was amused to learn another scientist had independently arrived at the same note-making method:

In some of his early letters he speaks of filling several note-books with facts for his book on species; but it was certainly early that he adopted his plan of using portfolios […] My father and M. de Candolle were mutually pleased to discover that they had adopted the same plan of classifying facts. De Candolle describes the method in his ‘Phytologie,’ and in his sketch of my father mentions the satisfaction he felt in seeing it in action at Down.

On realising they had arrived at the same note-making technique, Darwin wrote to the French-Swiss botanist Alphonse de Candolle, saying:

It has pleased me to find that I have always followed your plan of making notes on separate pieces of paper; I keep several scores of large portfolios, arranged on very thin shelves about two inches apart, fastened to the walls of my study, and each shelf has its proper name or title; and I can thus put at once every memorandum into its proper place.

The thin shelves Darwin used for filing his portfolios are clearly visible in the alcove to the right of the fireplace in this etching of his study made shortly after he died. I also note the same image appears to show several loose slips of paper pinned to the wall at the side of the fireplace:

Darwin’s study at Down House

de Candolle was just as delighted as Darwin to learn they shared the same loose-slip note-making technique. In a brief sketch he wrote about visiting Darwin at his home, de Candolle recalls (my translation of his original French, very much aided and abetted by Google Translate):

When we returned to the house [having walked round the grounds], Darwin showed me his library, a large room on the ground floor, very convenient for a studious man: many books on the shelves; daylight from two sides; a table for writing and another for experimental equipment. […] He was kind enough to inform me that, for his notes, he had himself employed exactly the same process of loose slips that my father and I have followed, and which I have spoken of in detail in my Phytographie. Eighty years of our [i.e. de Candolle and his father’s] experience had shown me its value. I am more impressed with it than ever, since Darwin had devised it on his own. This method gives the work more accuracy, supplements memory, and saves years.

Example of Darwin’s annotated notes in action

I thought it might be fun to explore an example of Darwin capturing and processing some notes, and using them in a published document.

For the source document, I chose On the Nature of Limbs by Darwin’s friend (and soon-to-be enemy), the brilliant anatomist Richard Owen. In this book, Owen describes how the skeletons of all vertebrates seem to bear the same underlying basic layout. Owen proposes this is due to their all being derived from the same ideal ‘archetype’. He suggests this mysterious underlying design must have arisen through natural laws, but offers no suggestions as to how.

Already familiar with Owen’s ideas, Darwin highlighted (with marginal pencil lines) several passages in his personal copy of ‘On the Nature of Limbs’, and included a number of annotations. Five of his highlights were made against the following:

  • on p.9, in which Owen points out that human inventors don’t constrain themselves to a common basic design when designing different types of mechanical locomotion;
  • on p.10, in which Owen argues that the structure of individual species’ limbs are not wholly determined by their ‘final causes’ (or, as we might put it, their forms are not entirely determined by their functions);
  • on pp.13–14, in which Owen points out the uncanny similarities in structure between a mole’s forelimb (used for digging), a human hand (used for grasping), a bat’s wing (used for flying), and the fin of a dugong or whale (used for swimming);
  • on p.82, in which Owen observes that the limbs of the newly discovered Lepidosiren (South American lungfish)—a species that can live out of water, and move around on land using its fins—most closely resemble the limbs of Owen’s hypothetical archetype;
  • on p.86, in which Owen waxes lyrical about how, once ‘the Divine Mind’ had planned and established the ideal archetype, ‘[Nature] has advanced with slow and stately steps, guided by the archetypal light, amidst the wreck of worlds, from the first embodiment of the Vertebrate idea under its old Ichthyic [i.e. fishy] vestment, until it became arrayed in the glorious garb of the Human form.’

In his indexed summary of his highlights and annotations that he pinned into the back of his copy of Owen’s book, Darwin summarised the highlighted sections described above as follows:

  • 9. Man does not trammel himself in his inventions by any common type
  • 13 Capital comparison of hand of Mole, Bat & Fin
  • 10 Final causes not sole governing principle [see also:] 14, 37
  • 82 Lepidosiren realises nearly ideal Archetype (see my remarks at end of volume)
  • 86 Alludes in grandiloquent sentence to some law governi[n]g progression, guided by archetypal light — &c.—

By far the most important (and famous) note Darwin made in his copy of On the Nature of Limbs, however, were the remarks he links to in the index item for p.82 shown above. In the back of the book, Darwin wrote a separate note offering his own interpretation of Owen’s proposed archetype:

I look at Owens Archetypus as more than ideal, as a real representation as far as the most consummate skill & loftiest generalizations can represent th parent-form of th Vertebrata . —

I follow him that there is a created archetype, the parent of its class

Darwin had realised that, when Owen talked of a mysterious vertebrate archetype, although he didn’t know it, he was really talking about the common ancestor of all vertebrates.

Darwin’s notes on Owen’s book were to inform his most famous work, On the Origin of Species, in which he writes:

Morphology.—We have seen that the members of the same class, independently of their habits of life, resemble each other in the general plan of their organisation. […] This is the most interesting department of natural history, and may be said to be its very soul. What can be more curious than that the hand of a man, formed for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and the wing of the bat, should all be constructed on the same pattern, and should include the same bones, in the same relative positions? […]

Nothing can be more hopeless than to attempt to explain this similarity of pattern in members of the same class, by utility or by the doctrine of final causes. The hopelessness of the attempt has been expressly admitted by Owen in his most interesting work on the ‘Nature of Limbs.’ On the ordinary view of the independent creation of each being, we can only say that so it is;—that it has so pleased the Creator to construct each animal and plant.

The explanation is manifest on the theory of the natural selection of successive slight modifications […] If we suppose that the ancient progenitor, the archetype as it may be called, of all mammals, had its limbs constructed on the existing general pattern, for whatever purpose they served, we can at once perceive the plain signification of the homologous construction of the limbs throughout the whole class.

Quite correct, as usual, Mr. D. The similar skeletal layouts of humans, moles, horses, porpoises and bats—and of frogs, lizards, birds, ichthyosaurs, and even fish—speak volumes. They speak of inheritance from a common ancestor. No other explanation makes sense.

Concluding remarks

Working, as I currently am, on a book about Charles Darwin, I’ve come to appreciate the importance of a reliable note-making system. I’m no note-making masochist, so, what with it being the twenty-first century and everything, I’ve adopted a highly flexible digital note-making app to gather and process my, and other people’s, thoughts. All such modern systems allow you to adopt Darwin’s top-down approach to note-making; or a bottom-up approach through which, by linking lots of small notes together, interesting new themes emerge; or, if you prefer, you can have a combination of both top-down and bottom-up. Each to their own.

Unsurprisingly, perhaps, because my main focus is currently on the life and work of a single person, I’ve mostly adopted Darwin’s top-down approach to note-making. This is not because I’m in any way trying to emulate my hero, but because a top-down approach, in this case, makes most sense. Darwin adopted a top-down approach to most of his work, so many of the notes in my electronic system naturally reflect the individual topics he worked on. Indeed, I suspect there must be a considerable overlap between the major topics covered in my notes, and the topics assigned their own loose-slip portfolios in Darwin’s own note-making system. That said, I have experienced several of my own bottom-up, mini Eureka moments as, deep down in some obscure note in my system, I’ve suddenly identified a fascinating, unexpected link with some apparently unrelated note elsewhere.

When you set out to unify the whole of biology by devising, researching and promoting its single most important theory, you’d better have a reliable note-making system to hand. Darwin would no doubt have given his back teeth for a modern, digital system to keep track of all his notes, but, obviously, this was never an option. So, instead, he devised his own, entirely pragmatic, top-down note-making system that allowed him to gather and process notes on all manner of different research topics from hundreds of different sources. The sheer amount of work he managed to put out bears magnificent testament to how well Darwin’s system worked for him.

Richard Carter’s newsletters

Subscribe to receive two free newsletters:

RICH TEXT: My personal newsletter about science, history and nature writing.

DARWIN NEWSLETTER: Celebrating the grandeur in Darwin’s view of life.


Leave a Reply

Your email address will not be published. Required fields are marked *